Arteriovenous Malformation

Overview Arteriovenous malformations (AVMs) are vascular lesions characterized by high flow pathologic shunting between the arterial and venous circulations with an intervening nidus of dysplastic vascular channels but no capillary bed. AVMs vary in degree of arterial supply, nidal size and location, flow-related aneurysms, and venous outflow. Lesions are typically within the subpial space supplied by the cerebral arteries, though AVMs often parasitize dural branches. Changes in the adjacent or underlying parenchyma identified on MRI and have been hypothesized to result from vascular steal phenomenon and venous congestion. Clinical symptomology is variable and generally related to intracranial hemorrhage. Occasionally, AVMs are discovered incidentally. Brain AVM, pial AVM, cerebral AVM, and non-Galenic CAVM are synonymous. Imaging General features Subpial space nidus, distinct from dural and subarachnoid AV shunts Supplied predominantly by pial arteries, may parasitize dur...

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